In recent years, a structural material of, for example, aircrafts is shifting from aluminum alloy to carbon-fiber reinforced plastics (CFRP) for weight saving, and the CFRP composite material is beginning to be used also as the material of main wings of the aircrafts. Each of such main wings, which can load fuel therein, has an I-shaped reinforcing rib made of aluminum alloy and two CFRP plates arranged on the top and bottom of the reinforcing ribs. FIG. 11 shows an illustration of means for joining the I-shaped reinforcing rib and one of the CFRP composite plates. The means includes: boring a through hole 101 in a layer of a CFRP composite plate 102 and an aluminum alloy plate 103; spot facing the end of the through hole 101 into a tapered shape; fitting a stainless steel sleeve S in the through hole 101; and forcing a titanium fastener F as a fastening member into the through hole 101. A liquid-tight structure of the main wing can thus be achieved.
However, the sleeve used in the main wing of the aircraft has a thickness of 0.1 to 0.2 mm, i.e. is very thin. Therefore, when the fastener is forced into the through hole, and the sleeve is forced against the inner wall of the through hole, the sleeve can crack and fracture in the middle portion thereof and come out of the surface opposite from the surface wherefrom the fastener is inserted. Furthermore, in some cases where spot facing in the end of the through hole is insufficient, the sleeve cannot completely fit in the through hole and extends beyond the outer surface of the CFRP plate. In these cases, the operator has to pull the fastener and the sleeve out of the through hole so as to replace them with new ones and/or to execute spot-facing work in the end of the through hole over again.
A puller for pulling out the sleeve out of the through hole in these cases is disclosed in, for example, Japanese Examined Patent Application Publication No. 55-32511. This art, as illustrated in FIG. 12, is used in a manner as follows: mate an in-low 4c of a screw rod guide 4 with an in-low portion 1b of a housing 1; clockwisely rotate a grip 8 so that a screw tap 3a of a screw rod 3 taps the inner surface of a blank cap 2; and, after finishing the tapping, clockwisely rotate a handle lever 6 to pull up the screw rod 3 and thereby detach the blind cap 2 from the housing 1.
In a case where a space for setting the puller and performing the pulling work is sufficiently large, the puller as described above is useful. However, in a case where the space for setting the puller and performing the pulling work is small, the puller is difficult to use. Moreover, depending on the location of the through hole, it is impossible to use the puller. Furthermore, while a comparatively big and thick member is easy to pull out using the puller, a very small and thin member (such as the member as above that is used in the main wing of the aircraft) is uneasy to pull out using the puller: during pull-out work, the sleeve can be fractured, and/or the inner wall of the hole can be damaged. This is a problem, and the puller is utterly unsuited to practical use due to the problem.
Thus, there is a need in the art for a puller that can be used for pulling out the metal sleeve inserted in the CFRP panel and, furthermore, is small-sized so as to be used in the small space.